Oscilloscope is an electronic device which plays a very important in the field of technology development because to be able to create an electronic device we need measuring instrument that can be used to analyze the properties of each component in the formation of the electronic devices that will be made in accordance with the purpose of manufacture. In order to have an oscilloscope that is portable, the device interface between the device and the computer system play an important role. USB is a standard communication port on the technology of today, therefore the portable digital oscilloscope is designed to use USB communication interface between the device and the computer. The portable digital oscilloscope devices must be able to read the input signal in the frequency range of the audio with maximum amplitude in the range + / - 20 Volts.